The present invention relates to crystalline inorganic materials containing at least one rare earth element, aluminum, boron and oxygen. In particular, new materials comprising crystalline LnAl.sub.1.67+0.67X (B.sub.4 O.sub.10)O.sub.X where Ln is at least one rare earth element ion having effective ionic radii less than about 0.98 Angstroms at valence 3+ and coordination number VI, and X is a number ranging from 0 to 1, having a characteristic X-ray diffraction pattern are described as well as the use of such materials in various catalyzed processes including partial oxidation and oxidative dehydrogenation of hydrocarbons and oxygen-containing hydrocarbons, dehydrogenation to functionalize alkylaromatic compounds, dealkylation of alkylaromatic compounds, and ammoxidation of alkylaromatic compounds. Also these new crystalline rare earth aluminum borates exhibit a variety of physical properties that make their use as optical materials attractive, including uses for optical frequency conversion, fluorescence, and laser materials.
The use of an active metallo element or a supported metallo element composition containing aluminum and boron as a conversion catalyst is known in the art. U.S. Pat. No. 3,883,442 to McArthur is illustrative of prior art disclosing the superiority of a supported active metal catalyst to resist shrinkage at high temperatures (up to 1600.degree. C.) by stabilization of a preformed alumina catalyst support. McArthur states stabilization was achieved by impregnating an alumina support with a solution of a boron compound which is thermally decomposable to B.sub.2 O.sub.3, followed by drying and calcining of the impregnated support at temperatures below about 1500.degree. C., but sufficiently high to decompose the boron compound. McArthur also discloses that the most commonly used technique of preparing a supported metallo element catalyst involved, following calcination, impregnating in conventional manner the alumina support material containing some retained B.sub.2 O.sub.3 with a solution of the desired metal salt, preferably those that are thermally decomposable to give the corresponding metal oxides and/or sulfides, and calcining the salt-impregnated support to convert the impregnated salt to the active catalytic form. McArthur neither discloses nor suggests a mixed oxide composition of a rare-earth element, aluminum, and boron.
In U.S. Pat. No. 3,954,670 to Pine, a boria-alumina based catalyst is disclosed in the combination of a metallo element and a boria-alumina catalyst support material prepared by hydrolysis of a mixture of aluminum alkoxide and boron alkoxide in the presence of water at a temperature in the range of 20.degree. to 100.degree. C. The disclosed catalyst compositions, said to be useful for desulfurization, denitrogenation, reforming and other hydrocarbon conversion processes, included rare earths such as cesium, lanthanum, neodymium, etc. as metallo elements in combinations with the boria-alumina catalyst composition disclosed in Pine and, optionally, a crystalline aluminosilicate zeolite with or without rare earth elements. However, Pine neither discloses nor suggests any crystalline mixed oxide composition of a rare-earth element, aluminum, and boron.
Zletz in U.S. Pat. No. 4,729,979, which is hereby incorporated by reference, discusses the characteristics of a good catalyst and/or catalyst support and a new crystalline copper aluminum borate characterized by a specific X-ray diffraction pattern, surface area and pore volume which is at least partially reducible with hydrogen at a temperature no more than 350.degree. C. to a composition containing zero valent copper and Al.sub.4 B.sub.2 O.sub.9. Satek in U.S. Pat. No. 4,590,324, which is hereby incorporated by reference, discusses using the new crystalline copper aluminum borate as a catalyst to dehydrogenate alkylaromatics to alkenylaromatics. Zletz et al. in U.S. Pat. No. 4,645,753, which is hereby incorporated by reference, discusses doping the new crystalline copper aluminum borate to contain an alkali metal or alkaline earth metal element for use as a catalyst to dehydrogenate alkylaromatics to alkenylaromatics. The Zletz, Satek, and Zletz et al. patents alone or in combination neither disclose nor suggest a mixed oxide composition of aluminum, boron, and a metallo element without copper. Furthermore, these patents disclose crystalline copper aluminum borate having significant X-ray diffraction lines which are substantially different from X-ray diffraction patterns for crystalline materials of the present invention.
A. A. Ballman discloses the preparation of rare earth aluminum borates from a molten solution with the general formula RAl.sub.3 B.sub.4 O.sub.12 where R was yttrium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, ytterbium and erbium in American Mineralogist 47, 1380-1383, (1962), "A New Series of Synthetic Borates Isostructural with the Carbonate Mineral Huntite" which is hereby incorporated by reference. A molten solution of potassium sulfate and molybdic anhydride (1:3 mole ratio) or lead fluoride and boric oxide (1:3 mole ratio) were used to dissolve the component oxides and produced single crystals ranging in size from about 0.1-10 mm when slowly cooled from 1150.degree. to 900.degree. C. The rare earth aluminum borates produced by the indicated route are believed to be well-defined, dense crystalline particles which have an extremely low surface area due to heating a mixture of oxides to a temperature of 1150.degree. C. Ballman neither discloses nor suggests a mixed oxide composition of aluminum, boron,, and a rare earth element having an aluminum to boron ratio less than 3/4 . Furthermore, the crystalline compounds disclosed by Ballman are characterized by having significant X-ray diffraction lines which are substantially different from X-ray diffraction patterns for crystalline materials of the present invention.
Kong Hua-shuang, Zhang Shou-qing, He Chung-fan and Zhang Dao-biao disclose the preparation of NdAl.sub.2 (B.sub.4 O.sub.10)O.sub.0.5 crystals grown from solvent in Research Inorganic Materials, (1982-1983), 10-12, "X-ray Difin fraction Powder Data and Some Physical Properties of NdAl.sub.2 (B.sub.4 O.sub.10)O.sub.0.5 " which is hereby incorporated by reference. A molten solution of BaO-B.sub.2 O.sub.3 -NdAl.sub.3 (BO.sub.3).sub.4 was heated to 1120.degree. C. and maintained at that temperature for 13 hours, then cooled down to 900.degree. C. at the rate of 20.degree. C./hr by the authors to obtain "a lot of small and thin crystals." The crystalline material produced by the indicated route is believed to be well-defined, dense crystalline particles which have an extremely low surface due to heating a mixture of oxides to a temperature of 1120.degree. C.
A. V. Pashkova, O. V. Sorokina, N. I. Leonyuk, T. I. Timchenko, and N. V. Belov, disclose four double metaborates having the general formula TRAl.sub.1.67+0.67X (B.sub.4 O.sub.10)O.sub.X where TRis lanthanum, cerium, praseodymium, or neodymium and X varies from 0 to 1, Sov. Phys, Dokl. 26(5), 457-459 (May 1981). Crystals of these materials were obtained from solution in a melt of potassium trimolybdate by crystallization in the form of hexagonal plates at temperatures in the range of 1100.degree. to 800.degree. C. by smoothly lowering the temperature at a rate of 0.5.degree. to 2.degree. C./hr. The authors state that their attempts to obtain dimetaborates of other rare earth elements by the same method did not yield positive results.
In the Pashkova paper, FIG. 2. shows a relationship between unit-cell parameters of four TRAl-dimetaborates and ionic radius of TR elements where TR is lanthanum, cerium, praseodymium, or neodymium. The authors state that, under the given conditions, the borates obtained are stable only for elements at the beginning of the rare-earth series, i.e., for elements having ionic radii in a range from the ionic radius of lanthanum to the ionic radius of neodymium.
The effective ionic radii of Shannon & Prewitt, Acta Cryst. (1969), B25, 925-945, have been revised to include more unusual oxidation states and coordinations by R. D. Shannon in Acta Cryst. (1976), A32, 751-767, incorporated herein by reference. Effective ionic radii found in Shannon for selected elements at valence 3+ and coordination number VI are set out below.
______________________________________ Effective Ionic Radii Ion.sup.1 IR.sup.2, .ANG. ______________________________________ Scandium, Sc 0.745 Indium, In 0.800 Lutetium, Lu 0.861 Ytterbium, Yb 0.868 Thulium, Tm 0.880 Erbium, Er 0.890 Holmium, Ho 0.901 Yttrium, Y 0.900 Dysprosium, Dy 0.912 Terbium, Tb 0.923 Gadolinium, Gd 0.938 Europium, Eu 0.947 Samarium, Sm 0.958 Promethium, Pm 0.970 Neodymium, Nd 0.983 Praseodymium, Pr 0.990 Cerium, Ce 1.01 Lanthanum, La 1.032 ______________________________________ .sup.1 Ion at valence 3+ and coordination number VI. .sup.2 Effective ionic radii in Angstroms, .ANG..
The general object of the present invention is to provide new crystalline materials having chemical and physical characteristics that make them useful catalytically and/or optically.
Another general object of this invention is to produce a new solid material which is useful in various catalyzed processes including partial oxidation and/or oxidative dehydrogenation of hydrocarbons and oxygen-containing hydrocarbons, in dehydrogenation of alkylaromatic compounds, in dealkylation of alkyaromatic compounds, and in ammoxidation of alkylaromatic compounds.
Another general object of this invention is to produce new synthetic crystalline compositions which are useful as frequency doubling materials in laser applications, and/or fluorescence materials.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims.